Merocarbocyanine dyes and photographic emulsions containing the same



Patented July 11,1939 I Q 2,165,338,;

UNITED STATES PATENT OFFICE,

MEROCARBOCYANINE DYES AND PHOTO- ggtfiEPHIC EMULSIONS CONTAINING THE Leslie. G. S. Brooker and Frank L. Whitefltochester, N. Y., assignors, by mesne assignments, to

Eastman Kodak Company, Rochester, N Y., a corporation of New Jersey Application August 13, 1936, Serial No. 95,931 In Great Britain August 15, 1935 12 Claims. (01. 95-7) This invention relates to merocarbocyanine turic and the like. Such heterocyclic nuclei are dyes and photographic emulsions containing the characterized by the following nuclear grouping: same. More particularly this invention relates I n to chain-substituted merocarbocyanine dyes and 150' Photographic emulsions. containing, as lights wherein A represents an atom such as oxygen or 5 sensitive material, silver salts, and containing as h sensitizing material, cha -subs u d e o The following examples serve to illustrate the bocyanine dyes. preparation of the dyes of our invention but are The dyes which go to make up the emulsions notintended to limitour invention. 10 of our inventions are in themselves new and can Example 1.3-Eth1 l-5-[.(1-ethyl-2(1)-p-naphbe represented by the Iollowmg general formula. thothiazylidenle) isomowlidene] Thodanme i f 2.69 g. (1 mol.) of 2acetylmethylene-I-ethylp-naphthothiazoline and 1.61 g. (1 mol.) of 3-v R ethylrhodanine were refluxed for about min- 15 utes in 15 cc. acetic anhydride. The dye separated from the chilled reaction mixture after several days standing at 0 C. The crude dye -was twice recrystallized irom: glacial acetic acid btained in the form of green needles methyl, n-butyl, phenyl or fury], Y represents the and 0 o non-metallic atoms necessary to complete an meltvmg at 251453 with decompositionarylothiazole or aryloselenazole nucleus and Z Example 2.5-[(1-etI wl-2(1)-p-naphthothiazylrepresents the non-metallic atoms necessary to idene)-isopropylidenel-rhodanine wherein A represents an atom, such as oxygen or sulfur, R represents anorganic residue, such as an alkyl group, R represents an organic residue, such as an alkyl or an aryl group, for example heterocyclic nucleus. .7

' -na hthothiazoline and 1.33 g. .(1. mol.) of The y of our Invention can be prepared by fhodgnine were refluxed in 15 cc. of acetic ancondensmg an acylmethylene derivative of an hydride for about 15 minutes The dye arylotmazolme an arylwelenmnne' with arated from the chilled reaction mixture after hetemcycnc 'cc'mpound containing nuclear I standing several daysat 0* C After recrystal- 30 active methylene group- The reaction can be lization from glacial acetic acid, the dye was obillustrated by the condensation of l-acetylmetht m as a very dark crystalline powder melting ylene-2-ethyl benzothiazoline with barbituric t 264-265. C. with decomposition.

acid, in the presence of acetic anhydride. Example 3 3 Phen et'wbz n a Pb 35 CH; (lo-NH thothiazylidene) -isopropu1idene] -rhodani 1l'e J (cmco o I v C -O+HIC O0-- 2.69 g. (1 mol.) of 2-acetylmethylene-l-ethyl- N p-naphthothiazoline and 2.09 g. (1 mol.) of 3- d phenylrhodanine were refluxed in 15 cc. acetic 40 e anhydride for about 15 minutes. The dye sep- 40 S OO NH arated from the chilled reaction mixture after standing about 4 days at'0 C. After recrystal- C=CH lization from glacial acetic acid, the dye was ob- N (JO-NH tained as green crystals melting at 299-300 C. 2H5 with decomposition. 45

Example 4.'--3-Ethyl-5- (1 -eth'yZ-2 (1 -p-naphthothiazylidene) -isoprop1llidene] 2 thi o 2,4 (3,5) oxazoledione Other water-binding agents can be used in the process; for example propionic anhydride, butyric anhydride, or the like.

Arylothlazoline or aryloselenazoline acylmeth- 2.69 g. (1 mol.) of 2-acetylmethylene-l-eth l- 60 ylene derivatives can be similarly condensed with p-naphthothiazoline and 1.45 g. (1 mol.) of 3- other barbituric acids or other heterocyclic nuclei ethyl-2-thio-2, ,5) -oxazoledione were refluxed such as rhodanine, 3-alkyl-rhodanines, 3+arylfor about 20 minutes in 15 cc. of acetic anhydride. rhodanines, 2 thio 2,4(3,5) oxazoledione, 3- p The dye separated from the chilled reaction mixalkyl 2 thiO ,4(3,5) -oxazoledione, thiobarbiture after four days standing at 0 C. The dye 55 a five-member six-member 2.69 g. (1 mol.) of 2-acetylmethylene-l-ethyl- 2 was recrystallized from glacial acetic acid and obtained as reddish crystals melting at 254- 256 C.

Example 5 .5- (1 -eth:1;l-2 (1 -p-na.phthothiaaylidene) -,isoprpylidene-] 2 thz'o -2,4,6-trilcefohexahydro-pyrmz'dine 2.69 g. (1 mol.) of 2-acetylmethylene-l-ethylp-naphthothiazoline and 1.44 g. (1 mol.) of thiobarbituric acid were refluxed in 15 cc. of acetic anhydride for about 30 seconds. The dye separated from the reaction mixture chilled to 0 C. After two recrystallizations from pyridine, the dye was obtained as minute orange crystals, melting at 301-302 C. with decomposition.

Example 6.3 -Phenyl- 5- l. (1 -ethyl-2 (1 -p-'naph.- thothiazylidene) -ethyl-ethylide1 ze] -rhodanine 2.83 g. (1 mol.) of 1-ethyl-2-propionyl-methylene-fl-naphthothiazoline and 2.09 g. (1 mol.) of 3-phenylrhodanine were refluxed in 15 cc. of acetic anhydride for about 30 minutes. The dye separated from the cooled reaction mixture after several days standing at 0 C. The crude dye was twice recrystallized from glacial acetic acid and obtained as green crystals melting at 266-268 C. with decomposition.

Example 7.'3-EthyZ-5- (Z-ethyl-I (2) -benzo'thiarr lidene) -is opropylidenel -2-thi0-2,4, (3,5) -o:cazoled'imze y 2.19 g. (1 mol.) of 1-acetylmethylene-2-ethylbenzothiazoline and 1.45 g. (1 mol.) of 3-ethyl- 2,4(3,5) -oxazoledione were refluxed in 25 cc. of acetic anhydride for 45 minutes. The dye separated from the cooled reaction mixture which had been diluted with ether after 2 days standing at 0 C. The crude dye was recrystallized from glacial acetic acid and obtained as minute light orange crystals, melting at 206-207" C. with decomposition.

Example s.-5- [CZ-Ethyl 1 (2) benzothz'azylidene) isopropylidene] 2 thio 2,4,6-trilcetohexahydropyrimidine 2.19 g. (1 mol.) of 1-acetylmethylene-2-ethylbenzothiazoline and 1.4 g. (1 mol.) of thiobarbituric acid were refluxed in 25 cc. of acetic anhydride for about thirty seconds. The dye separated from the cooled reaction mixture at 0 C. After recrystallization twice from pyridine the dye was obtained as minute light orange crystals,

Example 9.--u- (1 -Ethyl-2 (1) -p-naphth0thiazylidene) isopropylidene] -benzoylacet0nitrile 2.69 g. (1 mol.) of 2-acetylmethylene-l-ethylfl-naphthothiazoline and 1.45 g. (1 mol.) of benzoylacetonitrile were refluxed for about 20 minutes in 15 cc. of acetic anhydride. The dye separated from the reaction mixture cooled to 0 C. after several-days standing. After two recrystallizations from glacial acetic acid, the dye was obtained as pink needles, melting at 235-237 C. with decomposition.

The acylmethylene derivatives used herein can be prepared by condensing a cyclammonium quaternary salt, containing a reactive methyl group, with an acyl chloride or other halide in the presence of a base, advantageously a strong tertiary organic base. See our copending application, Serial No. 29,916, filed July 5, 1935 (now United States Patent No. 2,112,139, dated March 29 1938).

These new merocyanine dyes show a novel sensitizing action in photographic silver salt emulsions, particularly silver chloride and silver broinide emulsions. Accordingly, our invention is particularly directed to the customarily employed silver halide emulsions. However, the light-sensitive material employed in the emulsions of our inventioncan be any light-sensitive silver salt alone or combined with another light-sensitive silver salt, such as a silver halide. Our invention is further particularly directed to the customarily employed gelatin emulsions, gelatin being the carrier or medium in which the light-sensitive salt is suspended. However, any other suitable, carrier, such as a cellulose derivative or a synthetic resin, which has subsantially no desensitizing effect on the silver salt, can be used.

The sensitizing effect of these new dyes will be illustrated with reference to gelatino-silver-bromide emulsions. These illustrations will be made with particular reference to the dyes from rhodanines and 3-alkyl-2-thio-2,4(3,5)-oxazoledione with naphthothiazoles, as these dyes have proven particularly useful. Fig. 1 represents a gelatinosilver-bromide emulsion, containing 3-ethyl-5- [(1-ethy1-2(1) -p-naphthothiazylidene) -isopropylidenel-rhodanine; Fig. 2, a bromide emulsion containing 3-ethyl-5-E (l-ethyl-2(1) -fi-naphthothiazylidene) isopropylidene] 2 thio-2,4(3,5) oxazoledione; Fig. 3, a bromide emulsion containing 3-phenyl-5-l (1-ethyl-2 1) -p-naphthothiazylidene) -ethyl-ethylidene] -rhodanine; Fig. 4, a bromide emulsion containing 3-ethyl-5 [(2- ethyl 1(2) -benzothiazylidene) -isopropylidenel 2-thio-2,4(3,5) -oxazoledione; Fig. 5, a bromide emulsion containing 5-'-[ (1-ethyl-2(1) -}3-naphthothiazylidene) isopropylidenel rhodanine. Some of the herein disclosed dyes show small desensitizing efiects together with sensitizing efiects in another region of the spectrum. The. nuclei of the dyes may be substituted by groups such as alkyl, alkoxy, amino, chloro and the like.

In the preparation of photographic emulsions containing these new dyes, it is only necessary to disperse, homogeneously and uniformly, from about 5 to about 100 mg. of the dye or mixture of dyes in about 1000 cc. of the flowable emulsion, the concentration of dye being varied according to the type of light-sensitive salt which goes to make up the emulsion and according to the effects desired. The suitable and most economical concentration for any given emulsion will be apparent to those skilled in the art, upon making the ordinary tests and observations customarily used in the art of emulsion-making. To prepare a gelatino-silver-halide emulsion, the following procedure is satisfactory: A quantity of the dye is dissolved in methyl alcohol pyridine or acetone and a volume of this solution (which may be diluted with water) containing from 5 to 100 mg. of dye is slowly added to about 1000 cc. of a gelatino-silver-halide emulsion with stirring. Stirring is continued until the dye is uniformly and practically homogeneously dispersed.

With the more powerful of these new sensitizing dyes 10 to 20 mg. of dye per 1000 cc. of emulsion suffice to produce the maximum sensitizing effect with the ordinary gelatino-silver-halide emulsions. The above statements are only illustrative and not to be understood as limiting our invention in'any sense, as it will be apparent that these dyes can be incorporated by other methods in many of the photographic emulsions customarily employed in the art, such for instance as by bathing, the plate or film, upon which the emulsion has been coated, in a solution of the dye in an appropriate solvent, although such a method is ordinarily not to be preferred. The claims are intended to cover any combination of these new dyes with a photographic silver salt emulsion whereby the dye exerts a sensitizing effect upon the emulsions as well as a photographic element comprising a support, ordinarily transparent, upon which the light-sensitive emulsion is coated or spread and permitted to set or dry.

'Ihe herein disclosed dyes are useful in the construction of light filters. The dyes arealso useful as coloring matters for textiles, particularly cellulose acetate silk or the like.

It is to be understood that the herein disclosed dyes probably exist in two forms illustrated as follows:

As illustrated these forms are interconvertible one into the other, i. e. the forms are virtual tautomers.

What we claim as our invention and desire to be secured by Letters Patent of the United States of America is:

l. A photographic silver salt emulsion containing a sensitizing dye selectedfrom the group of dyes characterized by the following formula:

/Y\ R /Z\ rl-b=cH-('1=d--b=1l i wherein A represents an atom selected from the wherein A represents an atom selected from the group consisting of oxygen and sulfur, R represents an alkyl group, R represents an organic residue selected from the group consisting of cleus selected from the group consisting of benzothiazole, benzoselenazole, naphthothiazole and naphthoselenazole and Z represents the nonbered and six-membered heterocyclic nuclei.

3. A photographic gelatino-silver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula:

wherein A represents an atom selected from the group consisting of oxygen and sulfur, R. represents an alkyl group, R represents an organic residue selected from the group consisting of alkyl groups and aryl groups, Y represents the non-metallic atoms necessary to complete a nucleus selected from the group consisting of benzothiazole, benzoselenazole, naphthothiazole and naphthoselenazole and Z represents the nonmetallic atoms necessary to complete a nucleus selected from the group consisting of five-membered and six-membered heterocyclic nuclei.

4. A photographic-gelatino-silver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula':

' sion containing a sensitizing dye selected from the group of dyes characterized by the following formula: 1

wherein A represents an atom selected from the group consisting of oxygen and sulfur, R represents an alkyl group, R represents an alkyl group,

Y represents the non-metallic atoms necessary to complete a naphthothiazole nucleus, and Z represents the non-metallic atoms necessary to complete a nucleus selected from the group consisting of five-memb'ered and six-membered heterocycllc nuclei.

6. A photographic-gelatino-silver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula:

wherein A represents an atom selected from the group consisting of oxygen and sulfur, R represents an alkyl group, R represents an alkyl group, Y represents the non-metallic atoms necessary to complete a. p-naphthothiazole nucleus, and Z represents the non-metallic atoms necessary to -metallic atoms necessary to complete a nucleus I selected from the groups consisting of five-mem complete a nucleus selected from the group consisting of five-membered and six-membered heterocyclic nuclei.

7. A photographic-gelatino-silver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula:

wherein R represents an alkyl group, R represents an alkyl group, Y represents the nonmetallic atoms necessary to complete a p-naphthothiazole nucleusancl Z represents the nonmetallio atoms necessary to complete a rhodanine nucleus. 7

8. A photographic-gelatino-silver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula:

wherein R represents an alkyl group, R repre sents an alkyl group, Y represents the non-metallic atoms necessary to complete a B-naphthothiazole nucleus and Z represents the non-metallic atoms necessary to complete a 2,4,6-triketohexahydropyrimidine nucleus.

9. A photographic-gelatinosilver-halide emulsion containing a sensitizing dye selected from the group of dyes characterized by the following formula: 

